Franco Cicirelli Angelo Furfaro Libero Nigro Model checking time-dependent system specifications using Time Stream Petri Nets and Uppaal. 8160-8186 2012 218 Appl. Math. Comput. 16 https://doi.org/10.1016/j.amc.2012.02.018 db/journals/amc/amc218.html#CicirelliFN12